Congenital toxoplasmosis: diagnosis by exfoliative cytology

Toxoplasmosis, caused by the intracellular protozoan Toxoplasma gondii, has as its major routes of acquisition either ingestion (of the cyst or oocyte) or transplacental infection (by trophozoites). Transplacental transmission occurs to the fetus in utero or to the newborn at vaginal delivery. Maternally acquired infections can infect the embryo as early as the 7th week of gestation. It has been estimated that 15-17% of maternal infections acquired between the 7th and 14th weeks of gestation are transmitted to the embryo (Lynfield R, Eaton RB., Teratology 1995;52:176-180.). We present a 7-wk-old white male, delivered at 38 wk of gestation, who shortly after birth was found to have hepatosplenomegaly and anemia; he developed liver failure and ascites with persistent anemia during the first week of life. After an extensive, but nondiagnostic, work-up, a paracentesis was performed which led to a diagnosis of congenital toxoplasmosis. This case demonstrates the utility of exfoliative cytology in determining the cause of neonatal ascites, especially of an infectious etiology. To our knowledge, this represents the first reported case of Toxoplasma gondii diagnosed by exfoliative cytology in a pediatric patient.